Respect relative path names within configuration file

This applies to both the function file as well as module files.

Author: amotl

CHANGES.rst

@@ -6,7 +6,13 @@ mqttwarn changelog
 in progress
 ===========
 
+
+2021-06-03 0.22.0
+=================
+
 - [build] Fix unwanted cache hits when automatically building Docker images. Thanks, Gergő!
+- [core] Respect relative path names within configuration file. This applies
+  to both the function file as well as module files.
 
 
 2021-06-03 0.21.0
@@ -20,7 +26,7 @@ in progress
   responds with MQTT publish. Thanks, Jörg!
 - [core] Remove "os.chdir" as it is apparently not needed anymore. Thanks, Dan!
 - [ci] Run tests on Python 3.9, remove testing on Python 3.5
-- [core] Load service plugins from both modules and files
+- [core] Load service plugins from both modules and files.
 
 
 2020-10-20 0.20.0

mqttwarn/configuration.py

@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-# (c) 2014-2019 The mqttwarn developers
+# (c) 2014-2021 The mqttwarn developers
 import os
 import sys
 import ast
@@ -35,6 +35,8 @@ def __init__(self, configuration_file, defaults=None):
         self.read_file(f)
         f.close()
 
+        self.configuration_path = os.path.dirname(configuration_file)
+
         ''' set defaults '''
         self.hostname     = 'localhost'
         self.port         = 1883
@@ -81,7 +83,20 @@ def __init__(self, configuration_file, defaults=None):
                 self.tls_version = ssl.PROTOCOL_SSLv3
 
         self.loglevelnumber = self.level2number(self.loglevel)
-        self.functions = load_functions(self.functions)
+
+        # Load function file as given (backward-compatibility).
+        if os.path.isfile(self.functions):
+            functions_file = self.functions
+
+        # Load function file as given if path is absolute.
+        elif os.path.isabs(self.functions):
+            functions_file = self.functions
+
+        # Load function file relative to path of configuration file if path is relative.
+        else:
+            functions_file = os.path.join(self.configuration_path, self.functions)
+
+        self.functions = load_functions(functions_file)
 
 
     def level2number(self, level):

mqttwarn/core.py

@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-# (c) 2014-2020 The mqttwarn developers
+# (c) 2014-2021 The mqttwarn developers
 from builtins import object
 from past.builtins import cmp
 from builtins import chr
@@ -532,9 +532,15 @@ def load_services(services):
 
         module = cf.g('config:' + service, 'module', service)
 
+        # Load external service from file.
+        modulefile_candidates = []
         if module.endswith(".py"):
-            modulefile = module
+            # Add two candidates: a) Use the file as given and b) treat the file as relative to
+            # the directory of the configuration file. That retains backward compatibility.
+            modulefile_candidates.append(module)
+            modulefile_candidates.append(os.path.join(cf.configuration_path, module))
 
+        # Load external service with module specification.
         elif '.' in module:
             logger.debug('Trying to load service "{}" from module "{}"'.format(service, module))
             try:
@@ -544,15 +550,19 @@ def load_services(services):
             except Exception as ex:
                 logger.exception('Unable to load service "{}" from module "{}": {}'.format(service, module, ex))
 
+        # Load built-in service module.
         else:
-            modulefile = resource_filename('mqttwarn.services', module + '.py')
+            modulefile_candidates = [ resource_filename('mqttwarn.services', module + '.py') ]
 
-        logger.debug('Trying to load service "{}" from file "{}"'.format(service, modulefile))
-        try:
-            service_plugins[service]['module'] = load_module_from_file(modulefile)
-            logger.info('Successfully loaded service "{}"'.format(service))
-        except Exception as ex:
-            logger.exception('Unable to load service "{}" from file "{}": {}'.format(service, modulefile, ex))
+        for modulefile in modulefile_candidates:
+            if not os.path.isfile(modulefile):
+                continue
+            logger.debug('Trying to load service "{}" from file "{}"'.format(service, modulefile))
+            try:
+                service_plugins[service]['module'] = load_module_from_file(modulefile)
+                logger.info('Successfully loaded service "{}"'.format(service))
+            except Exception as ex:
+                logger.exception('Unable to load service "{}" from file "{}": {}'.format(service, modulefile, ex))
 
 
 def connect():

tests/__init__.py

@@ -3,5 +3,6 @@
 
 # Configuration- and function files used by the test harness
 configfile = 'tests/selftest.ini'
+configfile_v2 = 'tests/selftest_v2.ini'
 funcfile = 'tests/selftest.py'
 bad_funcfile = 'tests/bad_funcs.py'

tests/selftest_v2.ini

@@ -0,0 +1,49 @@
+# -*- coding: utf-8 -*-
+# (c) 2014-2021 The mqttwarn developers
+#
+# mqttwarn configuration file for testing function and module loading with relative paths.
+#
+
+; ------------------------------------------
+;             Base configuration
+; ------------------------------------------
+
+[defaults]
+
+
+; --------
+; Services
+; --------
+
+; path to file containing self-defined functions for formatmap and datamap
+; generate with "mqttwarn make-samplefuncs"
+functions = 'selftest.py'
+
+; name the service providers you will be using.
+launch    = tests.acme.foobar, acme/foobar.py
+
+
+[config:tests.acme.foobar]
+targets = {
+    'default'  : [ 'default' ],
+  }
+
+[config:acme/foobar.py]
+targets = {
+    'default'  : [ 'default' ],
+  }
+
+
+; -------
+; Targets
+; -------
+
+[test/plugin-module]
+; echo '{"name": "temperature", "value": 42.42}' | mosquitto_pub -h localhost -t test/plugin-module -l
+targets = tests.acme.foobar:default
+format = {name}: {value}
+
+[test/plugin-file]
+; echo '{"name": "temperature", "value": 42.42}' | mosquitto_pub -h localhost -t test/plugin-file -l
+targets = acme/foobar.py:default
+format = {name}: {value}

tests/test_core.py

@@ -7,8 +7,10 @@
 from builtins import str
 import logging
 
+import pytest
+
 from mqttwarn.core import make_service, decode_payload
-from tests import configfile
+from tests import configfile, configfile_v2
 from tests.util import core_bootstrap, send_message
 
 
@@ -167,9 +169,10 @@ def test_message_file_unicode():
         assert u'Räuber Hotzenplotz' in content, content
 
 
-def test_plugin_module(caplog):
+@pytest.mark.parametrize("configfile", [configfile, configfile_v2])
+def test_plugin_module(caplog, configfile):
     """
-    Check if using a module with dotted name also works.
+    Check if loading a service module with dotted name works.
     """
 
     with caplog.at_level(logging.DEBUG):
@@ -184,9 +187,10 @@ def test_plugin_module(caplog):
         assert 'Plugin invoked' in caplog.text, caplog.text
 
 
-def test_plugin_file(caplog):
+@pytest.mark.parametrize("configfile", [configfile, configfile_v2])
+def test_plugin_file(caplog, configfile):
     """
-    Check if using a module with dotted name also works.
+    Check if loading a service module from a file works.
     """
 
     with caplog.at_level(logging.DEBUG):